1. Field of the Invention
This invention resides in the field of biogas and its use as a source of energy.
2. Description of the Prior Art
The need for and interest in alternative sources of energy is continually increasing as crude oil prices continue to rise and as public awareness and concern over the effects on the environment of gaseous emissions from the processing of crude oil continue to grow. The disposal of municipal waste is also a perennial challenge as the rate at which the waste is generated continues to increase and as traditional means of disposal of the waste are faced with rising costs and increasing ecological concerns. Sources of municipal waste include everyday items such as product packaging, furniture, clothing, bottles and other discarded containers, food scraps, newspapers, appliances, paint, and batteries, as well as biomedical waste from hospitals, granular waste such as contaminated soil, liquid waste such as cooking oils, automotive oils, shale oil, and PCB oils, agricultural waste such as grass clippings, straw, wood, leaves, and plant matter in general, and industrial waste such as coal and lignite. The traditional methods of disposal include landfill and incineration, and the gaseous emissions from incineration contribute to air pollution and global warming.
One means of deriving value from municipal waste and waste products in general without incineration is biodegradation, which is the biological breakdown of organic matter in the absence of oxygen. The product of this breakdown is known as “biogas,” and the breakdown can be achieved by such processes as anaerobic digestion and fermentation of biodegradable materials such as biomass, manure, sewage, municipal waste, and energy crops. Depending on its source, biogas can include hydrogen, methane, and carbon monoxide, as well as relatively benign gases such as nitrogen and carbon dioxide.